1. Field of the Invention
The present invention relates to a glass frit, and more particularly, to a glass frit which has a good sealing effect with respect to moisture and gas and is processable at low temperatures, and a sealing method for an electric element using the same.
2. Description of the Related Art
Electric elements such as organic light emitting diodes, dye-sensitive solar cells and LEDs are required to be tightly sealed to minimize impacts from external moisture and gas and to improve performance and life thereof.
Particularly, there have been considerable studies about OLEDs in recent years as they can potentially apply to various areas and electroluminescent devices. For example, a single OLED can be used in a discrete light emitting device while an array of OLEDs can be applicable to an optical or flat panel display (e.g., OLED display). A typical OLED display has good contrast and a wide viewing angle. However, the OLED display, and particularly, an electrode and an organic layer included in the OLED can easily deteriorate by responding to oxygen and moisture in the OLED display. It is well known that the life of the OLED display may sharply rise if the electrode and organic layer within the OLED display are tightly sealed from the surrounding environment.
However, the size of the tight sealing should be as minimum as possible (e.g., <2 mm) in providing a barrier to oxygen (10−3 cc/m2/day) and water (10−6 g/m2/day). Also, the temperatures generated during the sealing process should not damage materials (e.g. electrodes and organic layers) within the OLED display as well as gas emitted during the operation should not contaminate the materials within the OLED display. As an electric connector (e.g., thin film chromium) should be within the OLED display, it was very difficult in the past to develop a sealing process to tightly seal the OLED display.
A general method of sealing the OLED display is to use epoxide, inorganic and/or organic materials forming the sealing after being processed with UV. For example, Vitex manufactures a coating agent named Barix™, which can be used to seal the OLED display with the inorganic and organic materials, based on access. Such a sealing method provides good physical intensity while it may not be cost effective. Also, there are many examples that diffusion of oxygen and moisture to the OLED display is not prevented.
Another method of sealing the OLED display is to use metal welding or soldering. In this case, there is a substantial difference between CTEs of a glass plate and metal in the OLED display, thereby failing to provide durability at a wide range of temperatures.
Thus, there have been continuous demands for addressing the foregoing problems and other weaknesses related to the typical sealing method for the OLED display. For example, Korean Patent First Publication No. 2006-0005369 discloses a method of tightly sealing an OLED element with a glass frit. Still, there have been requests for developing a more efficient sealing method for an electric element such as OLED, dye-sensitive solar cell, LED, etc. which are greatly affected by moisture and gas like oxygen.